St. Louis Cardinals starting pitcher Adam Wainwright (50) delivers a pitch to the Milwaukee Brewers in the third inning on April 11, 2018 at Busch Stadium in St. Louis. Photo by Bill Greenblatt/UPI | License Photo

In 2011, it was the Rally Squirrel dashing across home plate during Game 4 of the National League Division Series to disrupt Philadelphia pitcher Roy Oswalt and help the St. Louis Cardinals take a win-or-die game.

Six years later, the Rally Kitty appeared in center field just before a grand slam by Yadier Molina won an August game against Kansas City and fueled an eight-game winning streak that lifted St. Louis into a first-place tie in the NL Central before the Chicago Cubs finally pulled away.

On Sunday, Rally Squirrel II made a road trip, waltzing across the Comerica Park infield in Detroit moments before the Cardinals broke up a scoreless tie with five seventh-inning runs to notch a critical win over the Tigers and maintain their edge for the NL's second wild card.

"We'll look for that rally squirrel and try to bring it home," Cardinals second baseman Kolten Wong joked.

Given recent trends, St. Louis might need a whole zoo to try to figure out Pittsburgh Pirates right-hander Trevor Williams, its opponent Monday night for the beginning of a three-game series at Busch Stadium.

Williams (12-9, 3.15 ERA) continued an amazing run on Labor Day, firing 6 2/3 scoreless innings in a 5-1 win over Cincinnati at PNC Park. In his last nine starts, Williams has allowed only four runs in 54 2/3 innings, pitching scoreless ball six times and post an absurd 0.66 ERA.

One of those six times occurred two weeks ago, when he bagged a 2-0 win over the Cardinals (79-64) at Busch. Williams ceded only three hits and three walks in six innings, striking out eight.

"I'm confident in my ability to pitch at the big league level and have success at the big league level," he said to MLB.com after his win over Cincinnati. "It's just a matter of executing pitches."

Williams' shutdown outing against St. Louis reversed a career-long trend of struggles against a division rival. In 11 outings, he's 3-4 with a 5.98 ERA, permitting 59 hits in 43 2/3 innings and 29 earned runs.

The Cardinals would have avoided Williams had Pittsburgh (71-71) not been washed out of its series finale Sunday against Miami. The remnants of Tropical Storm Gordon moved that game back to Oct. 1, the day after the regular season was scheduled to end.

St. Louis will start veteran Adam Wainwright (1-3, 4.00), who has been out since May 13, when he suffered right elbow inflammation during the third inning of a 5-3 loss in San Diego. Wainwright has fired 17 scoreless innings across six rehab outings. In his career, Wainwright is 13-7 in 36 games with a 4.28 ERA when facing the Pirates.

"I feel like I'm getting called up for September," he said to MLB.com last week. "Earlier this season, I couldn't lift my bag, pick up my shirt, after starts. I threw a bullpen after my last start, and I didn't know what would happen. And I felt normal."

The Cardinals own a 9-7 edge in the season series with the Pirates, winning five of the seven games at home.